Residential and light commercial buildings usually are made up of at least three main elements: a foundation, walls, and a roof. For a multi-storied building, the adjacent stories are separated by a floor/ceiling structure which forms the floor of one story and the ceiling of the story below. The walls are constructed to withstand vertical and horizontal loads applied to the building. Static vertical loads can be applied to the building by, for example, the weight of snow collecting on the roof, while horizontal loads can be applied by high wind force against the side of the building. Dynamic vertical and horizontal loads can also be applied to the building by seismic activity and gusting winds. In addition to their load-carrying capacity, the walls serve to enclose the interior of the building to help keep out the elements and provide space through which essential building systems such as plumbing and electrical wire can be routed.
Given the important role the walls play in the durability and strength of a building, their construction is important. There are currently two main methods of constructing open frame walls of a building: the walls may be framed entirely in the field at a job site, or they may be framed by assembling many pre-fabricated panelized wall sections, including shear braces or shear panels, which are delivered to the job site. Each of these methods have several advantages and disadvantages.
In field framing, walls are typically framed so as to include shear panels at selected locations along the walls. The shear panel is designed to withstand anticipated maximum horizontal and vertical loads exerted on the building wall. A conventional field-framed shear panel is constructed by securing a series of vertical studs to cross members and to the foundation. Face sheets of a selected material, such as plywood, are attached to the studs to provide shear resistance. Flexibility is the main advantage of field framing, since the wall's section can be easily tailored to account for changes and irregularities in the job site. If, for example, the measurements of the foundation are slightly off, the contractor can easily construct the wall's sections, including the shear panels, to fit the foundation. The main disadvantage of field framing is that it is labor intensive and thus increases the construction cost. Furthermore, if any of the walls sustain significant damage, they are difficult and costly to repair or replace.
Framing using pre-fabricated panels usually involves joining several pre-fabricated panels, including shear panels, in a selected configuration to form the building walls. Pre-fabricated shear panels come in two main types. The first includes four structural members that form the perimeter of a quadrilateral, with a face sheet of a selected material, such as plywood, secured to the four structural members to give the panel shear strength. The second type of pre-fabricated shear panel is the type described in co-pending U.S. patent application Ser. No. 09/034,603, filed Mar. 3, 1998, and entitled HIGH STRESS RESISTANCE FRAME BUILDINGS AND METHOD APPARATUS FOR USE IN THE SAME, which is hereby incorporated in its entirety by reference thereto. This pre-fabricated shear panel includes four structural members in a quadrilateral arrangement and a pair of diagonal brace members extending between opposite corners of the quadrilateral. Thus, when a shear load is applied to the shear panel, the load is carried by tension and compression loads in the diagonal brace members.
The primary advantage of using pre-fabricated wall panels is ease and cost of construction: a building can be assembled more easily and quickly using pre-fabricated panels with the shear panels positioned at selected locations, thus reducing construction costs and total building time. But there are disadvantages. Using exclusively pre-fabricated panels make it difficult to adjust to irregularities in the job site. If, for example, the dimensions of the foundation are not what they should be, it is difficult to adjust the pre-fabricated panels to achieve a proper fit. Furthermore, the first type of pre-fabricated shear panel can restrict access to the wall and makes the job more difficult for subsequent subcontractors who must install components in the wall such as plumbing, insulation and electrical wire.
The diagonally braced shear panels are an improvement over the more traditional studs-and-plywood frame, but they experience other problems, most notably that the corners of the frame where the diagonal bands attach require a significant amount of hardware to provide an attachment that can withstand the loads transmitted through the diagonal brace members. This hardware results in a heavier and more expensive shear panel, thereby reducing the cost efficiency of using the panelized wall frames.